Back home in England, I was (coincidentally) photographing Tufted Ducks
yesterday. I can't see any reason from Phil Davis's photos to say it isn't a
Tufted Duck, but ruling out a hybrid is tricky. The extent of black on the bill
is variable in this species, but it is towards the more extensive end of the
variation in the Cambridge bird. Note also that Tufted Duck does have whitish
grey towards the nail area of the bill:
 
<http://www.pbase.com/andywilson/image/107902317>
<http://www.pbase.com/andywilson/image/107902341>
 
notice how extensive the black bill tip is in this female bird:
 
<http://www.pbase.com/andywilson/image/107902379><http://jjd.pbase.com/image/107902379>
 
Also, note that an adult male would have clean white sides, if it is a pure Tufted Duck, it's a first-winter male.
 
Hope it sticks around until I come back!
 
 


Andy Wilson
Frederick